A photosensitive composition may be used for curing a dielectric film or a passivation material and the like of a liquid crystal display (LCD). The photosensitive composition may be applied on a substrate to form a coating film and the coating film is entirely exposed to form an insulating film or a protective film, or may be used to form a pattern by performing exposure by light irradiation using a photomask and the like on a specific portion of the coating film, and then removing an exposed portion or non-exposed portion by developing treatment.
The photosensitive composition may be polymerized and cured by irradiating light and thus has been used for photocurable inks, photosensitive printing plates, various photoresists, color filter photoresists for LCDs, photoresists for a resin black matrix, or transparent photosensitive materials or the like.
Among them, the transparent photosensitive composition may be used to form a column spacer, an overcoat or a passivation film. The transparent photosensitive composition typically does not use coloring preparations such as pigments, and may be a liquid-state composition comprising an alkali soluble resin, a polymerizable compound having an ethylenically unsaturated bond, a photopolymerization initiator and a solvent. As the use of LCDs becomes high-quality and diversified, LCDs are being manufactured for the use of constituting liquid crystal display devices, such as TVs, monitors and the like in addition to the use of laptop computers, mobile phones and the like.
Recently, in order to enhance the brightness efficiency of LCDs, a case in which a TFT structure with increased apertures is applied has been increased. Thus, an organic thin film having excellent transmittance for light has been widely used as an insulating film.
Holes with a certain size may be formed in an organic thin film used in this case, in order to enable a gate line or a storage capacitor of a TFT to be connected to a pixel electrode.
In a method for forming holes, a positive-type photosensitive composition is advantageous, but there are problems such as a decrease in transmittance by a photoacid generator (PAG), heat resistance or the like.